Flow drag mitigation device

Abstract

A mitigating system for reducing flow drag in aircraft engines uses a mitigating device attached to either the nacelle of an engine to mitigate the flow drag of the airflow moving across the nacelle. The mitigating device has an inner sleeve and an outer sleeve, each of which can be adjusted separately to extend any desired length across the inner surface or outer surface of the nacelle. As the sleeves are extended, they cover a greater number of flow drag elements thereby improving the aerodynamic properties of the aircraft engine.

The invention claimed is: 
     
       1. A system for mitigating flow drag caused by airflow over a jet engine surface comprising:
 a. a housing having a first end and a second end, wherein said airflow moves from said first end of said housing toward said second end of said housing, further wherein said housing comprises flow drag elements, wherein said flow drag elements comprise a nose cowl having a first end and a second end and an inner surface and an outer surface, a fan cowl having a first end and a second end and an inner surface and an outer surface, and a lipskin having a lipskin leading edge and a second end and an inner surface and an outer surface; 
 b. a first plurality of fasteners, wherein said first plurality of fasteners connects said second end of said lipskin to said first end of said nose cowl thereby creating a first joint, wherein said first plurality of fasteners is located at said second end of said lipskin; 
 c. a second plurality of fasteners, wherein said second plurality of fasteners connects said second end of said lipskin to said first end of said nose cowl, wherein said second plurality of fasteners is located at said first end of said nose cowl; 
 d. a third plurality of fasteners, wherein said third plurality of fasteners connects said second end of said nose cowl to said first end of said fan cowl thereby causing a cowl interface having a nose cowl side and a fan cowl side thereby creating a second joint, wherein said third plurality of fasteners is located on said nose cowl side of said cowl interface; 
 e. a fourth plurality of fasteners, wherein said fourth plurality of fasteners connects said second end of said nose cowl to said first end of said fan, wherein said fourth plurality of fasteners is located on said fan cowl side of said cowl interface; and 
 f. a mitigating device having an outer sleeve, wherein said outer sleeve has a first end and a second end, wherein said mitigating device is connected to said housing, further wherein said mitigating device directs said airflow over said flow drag elements thereby reducing flow drag caused by said flow drag elements. 
 
     
     
       2. The system of  claim 1 , wherein said mitigating device further comprises an inner sleeve having a first end and a second end. 
     
     
       3. The system of  claim 2 , wherein said second end of said inner sleeve of said mitigating device extends to a point on said inner surface of said lipskin before said second end of said lipskin. 
     
     
       4. The system of  claim 2 , wherein said second end of said inner sleeve of said mitigating device extends over said second end of said lipskin thereby covering at least a portion of said inner surface of said lipskin. 
     
     
       5. The system of  claim 4 , further wherein said second end of said inner sleeve of said mitigating device extends over said first joint thereby covering said first joint. 
     
     
       6. The system of  claim 2 , wherein said inner sleeve of said mitigating device comprises acoustic absorbing surfaces. 
     
     
       7. The system of  claim 1 , wherein said mitigating device is connected to said lipskin leading edge, wherein said second end of said outer sleeve of said mitigating device extends to a point on said outer surface of said lipskin before said second end of said lipskin. 
     
     
       8. The system of  claim 1 , wherein said second end of said outer sleeve of said mitigating device extends over said second end of said lipskin thereby covering at least a portion of said outer surface of said lipskin and covering at least a portion of said first plurality of fasteners. 
     
     
       9. The system of  claim 8 , further wherein said second end of said outer sleeve of said mitigating device extends over said first joint thereby covering said first joint. 
     
     
       10. The system of  claim 9 , further wherein said second end of said outer sleeve of said mitigating device extends over said first end of said nose cowl to a point on said outer surface of said nose cowl before said second end of said nose cowl thereby covering a portion of said outer surface of said nose cowl and thereby covering said second plurality of fasteners. 
     
     
       11. The system of  claim 10 , further wherein said second end of said outer sleeve of said mitigating device extends over said second end of said nose cowl thereby covering said outer surface of said nose cowl and thereby covering said third plurality of fasteners. 
     
     
       12. The system of  claim 1 , wherein said outer sleeve of said mitigating device comprises acoustic absorbing surfaces. 
     
     
       13. The system of  claim 1 , further comprising an outside device attached to said first end of said mitigating device. 
     
     
       14. The system of  claim 1  wherein said housing is a nacelle. 
     
     
       15. The system of  claim 1 , wherein said mitigating device comprises an anti-icing device. 
     
     
       16. A mitigation device for reducing drag on an aircraft surface, the mitigation device comprising:
 a. an outer sleeve, wherein said outer sleeve has a first end and a second end; 
 b. an inner sleeve having a first and second end, 
 wherein said mitigating device is attached to said aircraft surface and wherein said mitigating device comprises a smooth mitigation device surface such that it directs airflow over said aircraft surface thereby reducing flow drag caused by flow drag elements of said aircraft surface, wherein said aircraft surface is a lipskin comprising an inner surface and an outer surface and a first and second end, and wherein said second end of said outer sleeve of said mitigating device extends to a point on said outer surface of said lipskin before said second end of said lipskin, further wherein said second end of said inner sleeve of said mitigating device extends to a point on said inner surface of said lipskin before said second end of said lipskin, further wherein said second end of said outer sleeve of said mitigating device extends over said second end of said lipskin thereby covering at least a portion of said outer surface of said lipskin, further wherein said second end of said inner sleeve of said mitigating device extends over said second end of said lipskin thereby covering at least a portion of said inner surface of said lipskin, and further wherein said aircraft surface further comprises a nose cowl comprising a first end and a second end and connected to the lipskin and defining a first joint therebetween, further wherein said second end of said outer sleeve of said mitigating device extends over said first joint thereby covering said first joint. 
 
     
     
       17. The mitigation device of  claim 16 , further wherein said second
 end of said inner sleeve of said mitigating device extends over said first joint thereby covering said first joint. 
 
     
     
       18. The mitigation device of  claim 17 , further wherein said second end of said outer sleeve of said mitigating device extends over said first end of said nose cowl to a point on said outer surface of said nose cowl before said second end of said nose cowl thereby covering a portion of said outer surface of said nose cowl. 
     
     
       19. The mitigation device of  claim 18 , further wherein said second end of said outer sleeve of said mitigating device extends over said second end of said nose cowl thereby covering said outer surface of said nose cowl.